Carpenter&#39;s square.



G. BICK.

CARPENTER'S SQUARE.

APPLICATION FILED AUG-30, 191a.-

Patented Aug. 14:, 19176 3:320 MEN GEURGE BECK, OF CBIKCAGO, 'QLLINGFES.

Application filed August 30, 1918.

To all whom it may concern:

it known that I, GEORGE Bron, a citi- Zen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and use ful Improvements in Carpenters Squares, of which the following is specification.

This invention relates to carpenters snares, which have impressed. on their fiat l A: 1 aces tables of calculations rurnishing data enable a carpenter or builder to easily and (richly ascertain the lengths of various kinds of rafters and braces, and to obtain other information concerning the same when the pitch and span of a root or similar structure are known.

The principal aim in providing tabulated squares oithis character is to facilitate the work-of a builder. It has beenliound, hon ever, that the majority of squares heretofore provided are crowded with tables and data which are unnecessary and are never referred to by the ordinary builder. Such tabulations tend to confuse and render the square valueless for the very purpose for which. it was designed. For example, carpenters squares will be found to contain tables relative to board measure brace measure, octagon, polygon and special angle cuts, and other indicia which enable one to ascertain the lengths and cuts of rafters of various classes such as common, hip and valley, cripple rafters, etc. it/hen complications of this diversified character are crowded onto the faces of a square, it will be evident that the usefulness is materially if not wholly, subverted by their complexity, since the ordinary carpenter is confused by the complexity of the data and cannot spend the time necessary to search out of such an array of figures only certain information that he has occasion to refer to very frequently in the ordinary course of his work.

The primary object of my invention is to provide a carpenters square, tabulated in such simple and novel manner as to effectively and practically serve the needs of a carpenter or builder in ordinary construction work. I have aimed to provide a tabulated square which will not confuse the caroenter, which contains a uniform array and a minimum number of figures arranged to denote a maximum amount or practical information for the carpenter.

To th s end have provided a one Specification of Letters lPatent.

Serial No. 117,580.

tables for ascertaining the length of common rafters and on the other side tables for the same purpose relative to hip and valley rafters. I have found that in practical work dimensions relative to all types of rafters and braces may be calculated under these two general heads, via, common, hio and valley rafters. The tables in both cases are simi larly laid out, and in referring to each for similar information the same method is followed. The only difference in the figures themselves which difierent because of the different character dimensions of the two general classes of rafters. Generally stated, the arrangement on one side, for example, the common rafter side, comprises a talole on the blade in registration with the inch markings thereon from which the length of common rafters and analogous types of rafters may be obtained when there is given the pitch of the root and the span in feet the inch marks on the blade representingfeet, and on the tongue a table from which similar results may be obtained when the span is in inches from 1 to 12 and in fractions of an inch. in other words, when the span is an even number or feet, the length of the rafter is obtained from the table on the blade alone. When the span includes inches less than one foot or fractions of an inch, the table on the tongue is reterred to to ascertain the length sought for the span in inches and fractions thereof separately. The sum of the results obtained separately from the span in feet, inches and fractions thereof gives the total length of the rafter, and, as will be explained hereinafter, these measurements for both classes of rafters take care of practically all conditions and give all the information necessary to be computed from tables for use in ordinary carpentry work.

Still another object of my invention is to provide a separable carpenters square so that the blade and tongue may be detached and easily packed and carried. have also aimed to materially improve and strengthen the joint between the blade and tongue so asto insure that these parts will he posi tively and accurately held in correct relative relation and at the same timernay be.

easily assembled and disassembled. Referring to the drawingsl' igure 1 is a view of one side of a carpenters square embed my improve for cslculations relative to hip and valley and similar rafters;

Fig. 2 is a view of the other side of the square, containing tables for calculations relative to common rafters and the like;

Fig. 3 is a face view of the elbow of the square with the markings removed to clearly illustrate the joint;

Figs. 4 and 5 are views of the joint end of the blade and tongue respectively;

Fig. 6 is a longitudinal sectional view through the blade on the line 6-6 of Fig. 3;

Fig. 7 is a View of the opposite side of the elbow portion from that shown in Fig. 3; and

Fig. 8 is a longitudinal sectional view through the tongue taken on the line 8--8 of Fig. 7. I

The blade 11 and tongue 12 are formed in separate parts detachably joined together at the elbow of the square. This joint of tenon and dovetail type, best shown in Figs. 3 to 8 inclusive, is designed to give maximum strength, as will be presently apparent. The inner end 13 of'the tongue forms the tenon which is substantially the same width as the tongue except for the cutaway 14 on its outer side. The edges l5, 16, 17 and 18 of the tenon are beveled so that the tenon will fit snugly in the groove 19 in the blade to form a dovetail connection or oint. The tenon is one-half the thickness of the body of the tongue and extends substantially across the blade. The under edge 21 of the tongue is undercut on a bevel through out the width thereof and engages a cone spondingly beveled face of the blade. A countersunk set-screw 22 passing centrally through the tenon is threaded into the blade to securely lock the two parts together. By reason of this construction a maximum length of dovetail face is obtained, and

the tongue and blade are so associated as to be positively locked and secured against relative displacement during usage.

Coming now to the tabulations and other information on the square, it will be noted that the edges of the square on both sides contain graduations in inches very similar to any ordinary square. In other words, the outer edge of the blade is graduated in inch markings up to 2% inches and suitably divided in fractionaf parts of an inch and-the outer edge of the tongue is similarly divided into inch narkings up to 16 inches. The inneredges of the tongue and blade are also graduated in inches as shown. Referring now to Fig. 2. which contains tables for common rafter calculations, it will be noted that the blade and tongue each contains a separate table.

' is for the purpose of calculating the length of the rafters anc'. the like when the pitch and also the spar. in feet of the roof are known. table on the tongue is for the That on the blade.

Lea er? purpose of obtaining similar information when the span is in inches from 1 to 12 and fractional parts of an inch. Referringagain to the table on the blade, it will be seen that from each inch mark columns of figures extend crosswise of the blade on opposite sides of lines 28 and the figures of these columns are arranged between parallel lines 24 extending lengthwise of the blade. At the extreme left of these parallel lines is a column of figures 25 denoting difi'erent pitches of a roof. These figures, viz., 6 to 12 inclusive, respectively designate the rise per foot in inches and I have found that invariably the pitches desired for ordinary usage will be found within this range. The v figures on the left hand side of the lines 23 denote feet and inches and those on the right hand side sixteenths of an inch. These figures are computed so that given the pitch andspan in feet of a roof they will show the exact length of a rafter. For example, if the span of a roof is seven feet and a nine inch rise is desired, the carpenter re fers to the figure 9 in the column 25 and traces the horizontal column in which 9 is located to the right until the vertical column under the 7" mark on the outer edge of the blade is reached, which shows 8 9", the length of the rafter. Thus the inch marks on the outer edge of the blade represent feet in connection with the calculations described. Should the span of the roof be greater than 24:, the length of the blade in inches, (30 for.instance), the calculation may be made by referring to the 15 column and doubling the results obtained, or the same result would be obtained by adding the figures in the proper pitch level found over the 10" and 20" columns. 4

Any measurements shorter than 1, that is relative to the span of the roof in inches or fractions thereof, are found on the table on v the blade. It will be seen that this table comspace 28 by a figure indicative of a certain span in inches, that is, the columns are des ignated by 1 to 12 inch markings and fractions of an inch from t to 501: an inch. At the extreme right of the table-is a column 29 containing the difi'erent pitches arranged similarly to those in the table on the blade. The method of procedure to ascertain the length of a rafter when the span and pitch is given is the same as described in connection with the table on the blade. If the span is 3 and the pitch 9", the figure 9 in the pitch column is referred to and this space followed to the left to the 3 column at which will be found the dimension 4:" 13,

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